JP2005000937A - Manufacturing method and apparatus for internally grooved tube - Google Patents

Abstract

A method and apparatus for manufacturing an internally grooved tube capable of mass-producing a long internally grooved tube at low cost without causing defects.
A grooved floating plug 3 having a groove forming portion 4 in which grooves 4a parallel to the tube axis are formed at predetermined intervals on an outer peripheral surface is disposed inside the smooth tube 10, and the grooved floating plug is provided. 3, a die 2 that is rotationally driven when the smooth tube 10 is drawn is disposed outside the smooth tube 10. The smooth tube 10 is pulled out while rotating the die 2, and the smooth tube 10 is subjected to reduction processing and internal groove forming, whereby an internal grooved tube 11 having an internal groove 11 a parallel to the tube axis is formed on the internal surface. can get.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for manufacturing an internally grooved tube, and in particular, an internal grooved tube manufacturing method that has an internal groove parallel to the tube axis and is optimal for use as a heat transfer tube or a leak detection tube. Relates to the device.
[0002]
[Prior art]
For example, heat exchangers are used in air conditioning equipment. One type of heat exchanger is a shell tube type, in which a large number of metal tubes (heat transfer tubes) are arranged in parallel in a circular cylinder, and a medium such as water is caused to flow in each metal tube. As the metal tube, a straight tube, a finned tube, and a grooved tube (inner surface grooved tube) in which a spiral groove or the like is provided on the inner surface to improve heat transfer characteristics are used.
[0003]
FIG. 3 shows a conventional internally grooved pipe manufacturing apparatus. This inner surface grooved tube manufacturing apparatus belongs to the drawing method, and a plug having a spiral groove at the tip is rotatably inserted into a metal tube (smooth tube), and further outside the plug through the smooth tube. A spiral groove can be formed on the inner surface of the tube by arranging a die and pulling out the smooth tube while rotating the plug with a mandrel (see, for example, Patent Document 1).
[0004]
An inner grooved pipe manufacturing apparatus 100 in FIG. 3 includes a base portion 101 installed horizontally on the ground and a die (not shown) for processing the smooth pipe 200 into an inner grooved pipe 201 having a desired outer diameter and inner groove. ) Installed inside, a position adjusting device 103 installed at the end on the base 101, a mandrel 104 with a plug (not shown) attached to the tip and inserted into the smooth tube 200, A rotation support portion 105 that is attached to the position adjustment device 103 and rotatably supports the end portion of the mandrel 104, a carriage 106 that pulls the distal end portion of the inner grooved tube 201 in the horizontal direction, and a carriage 106 in the base portion 101. Sprockets 107a and 107b disposed at both ends of the travel range of the vehicle and an endless chain suspended between the sprockets 107a and 107b 08, is constituted by a pawl 109 for connecting the predetermined position and the truck 106 of the chain 108. Here, the carriage 106, the sprockets 107a and 107b, the chain 108, and the claw 109 constitute a drawing device.
[0005]
FIG. 4 shows a detailed configuration of the processing unit 102 and the rotation support unit 105. A plug 110 is disposed in the processing portion 102, and the plug 110 is attached to the tip of the mandrel 104. The plug 110 has a spiral groove 110 a formed on the outer peripheral surface, and the groove shape is transferred to the inner surface of the smooth tube 200, whereby an inner surface groove 201 a is formed on the inner surface of the smooth tube 200. A die 111 is disposed outside the plug 110 with the smooth tube 200 sandwiched therebetween. The die 111 is housed in a die cover (not shown). This die cover is fixed to the base portion 101.
[0006]
The rear end portion of the mandrel 104 is interposed in the main body of the rotary support portion 105, and a disc-like stopper 104 a is attached. The end portion is rotatably supported by the thrust bearing 105 a at the rotary support portion 105. The stopper 104a prevents the mandrel 104 from being pulled into the inner grooved tube 201 when the inner grooved tube 201 is pulled out. A mandrel base portion 105 a is attached to the center of the main body of the rotation support portion 105, and the mandrel base portion 105 a is supported by the position adjusting device 103. In order for the inner surface groove 201a to be formed uniformly in the smooth tube 200, the mandrel 104 and the smooth tube 200 need to be positioned so as to be coaxial, but the adjustment is performed by the rotary support 105. Is called.
[0007]
3 and 4, the tip of the smooth tube 200 is inserted into a die 111, reduced in diameter by the die 111, and pulled out from the left side of the drawing. At this time, the carriage 106 is returned to the upper position of the sprocket 107 b, and the tip of the smooth tube 200 is connected to the carriage 106. Next, the mandrel 104 with the plug 110 attached is inserted into the smooth tube 200 from the right side of the figure. When the sprockets 107a and 107b are rotated in this state, the chain 108 is rotated, and accordingly, the carriage 106 is moved in the left direction. In the process, the smooth tube 200 is gradually pulled out from the die 111.
[0008]
When the smooth tube 200 is reduced in diameter by the die 111 as the smooth tube 200 is pulled out, the inner surface of the smooth tube 200 is pressed against the spiral groove provided on the outer peripheral surface of the plug 110, and the groove shape of the plug 110 is smooth. The inner surface grooved tube 201 is manufactured by being transferred to the inner surface of the tube 200.
[0009]
Also, the die and grooved plug are arranged coaxially, the smooth tube inserted through the die is pulled out, and at the same time the die is rotated, and in this process, the outer surface of the plug is pressed against the inner surface of the smooth tube, and the groove of the plug There has also been proposed a manufacturing method in which the shape is transferred to the inner surface of the smooth tube (see, for example, Patent Document 2).
[0010]
FIG. 5 shows another configuration of a conventional apparatus for producing an internally grooved tube. The inner surface grooved pipe manufacturing apparatus 300 includes a gap 301 corresponding to the thickness of the smooth pipe 304 and the plug 301 having a spiral groove formed on the outer peripheral surface, the floating plug 303 connected to the plug 301 via the connecting rod 302, and the like. The processing ball 305 provided and disposed around the plug 301, the die 306 disposed around the floating plug 303 with a gap corresponding to the thickness of the smooth tube 304, and the rear of the processing ball 305. And a die 307.
[0011]
In FIG. 5, a plug 301, a connecting rod 302, and a floating plug 303 are inserted into a smooth tube 304, and the smooth tube 304 is pulled out from the left side to the right side in FIG. When the smooth tube 304 first passes between the floating plug 303 and the die 306, the smooth tube 304 is reduced to a predetermined outer diameter (referred to as a process for reducing the outer diameter of the tube), and then rotates with the plug 301. When passing between the processed balls 305, the size is further reduced. At this time, since the spiral groove 301a is formed on the outer peripheral surface of the plug 301, the groove 301a of the plug 301 is transferred to the inner surface of the smooth tube 304 pressed against the plug 301 by the processing ball 305. An internally grooved tube 308 having a groove 308a is produced. The inner grooved tube 308 is further reduced to a predetermined outer diameter size by a die 307. The inner grooved tube manufacturing apparatus shown in FIG. 5 can process the inner surface groove of a long thin wall tube that cannot be achieved by the other manufacturing apparatuses described above.
[0012]
[Patent Document 1]
JP-A-49-31863 [Patent Document 2]
Japanese Examined Patent Publication No. 56-122612 [0013]
[Problems to be solved by the invention]
However, according to the conventional inner grooved tube manufacturing apparatus, the length of the inner grooved tube is limited by the size of the mandrel and the drawing device in the configuration of FIGS. 3 and 4 (the configuration of Patent Document 1). The processing of long materials is difficult. In addition, since the contact area between the plug surface in the pipe and the workpiece (smooth pipe 304) is large, the frictional force is large. Therefore, in the case of a thin-walled material, the pulling force is larger than the tensile strength of the workpiece, so that it easily breaks. Become.
[0014]
Furthermore, according to the configuration of Patent Document 2, since the grooved plug is held by the mandrel, the length of the mandrel is limited, and there is a limit to the processing of the long material. For example, an internally grooved tube of a long material of 100 m to 1000 m cannot be manufactured.
[0015]
Further, according to the configuration shown in FIG. 5, since the groove is formed by the rotation of the processing ball 305, there is a limit in increasing the rotation speed, and the processing speed cannot be increased, so that the productivity cannot be increased. Further, the apparatus configuration is complicated compared to the configuration of FIG.
[0016]
Accordingly, an object of the present invention is to provide a method and an apparatus for manufacturing an internally grooved tube capable of mass-producing a long internally grooved tube without causing defects.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides, as a first feature, a floating plug having a groove forming portion in which a plurality of grooves parallel to the tube axis are provided in the circumferential direction of the outer peripheral surface. The die is arranged outside the work tube so as to face the floating plug, the work tube is pulled out while rotating the die, and the work tube is reduced and the inner groove is formed. Provided is a method for manufacturing an internally grooved tube characterized by performing processing.
[0018]
According to this method, by pulling out the work tube while rotating the die, the frictional force on the surface of the work tube can be reduced, and the groove shape of the groove forming portion is a groove parallel to the tube axis. Therefore, it is possible to reduce the internal friction caused by grooving, improve the passage of the pipe to be processed at the time of drawing the pipe to be processed, and manufacture the internal grooved pipe at a high speed without causing defects such as breakage. Can do. Moreover, since a mandrel is not used, a long inner grooved tube can be manufactured.
[0019]
In order to achieve the above object, according to the present invention, as a second feature, a floating plug is disposed inside the work tube, and a first die is disposed outside the work tube so as to face the floating plug. A plurality of grooves parallel to the tube axis are formed in the circumferential direction of the outer peripheral surface, and the plug is disposed inside the processed tube in a state of being connected to the floating plug by a connecting rod. The second die is disposed outside the work tube so as to face the plug, the work tube is pulled out while rotating the first and second dies, and the work tube is reduced. And a method of manufacturing an internally grooved tube characterized by performing an internal groove forming process.
[0020]
According to this method, the friction force on the surface of the work tube can be reduced by pulling out the work tube through the floating plug and the grooved plug while rotating the first and second dies. In addition, since the groove shape of the plug is a groove parallel to the tube axis, the internal friction associated with grooving can be reduced, which improves the passage of the tube to be processed when drawing the tube to be processed, and causes defects such as breakage. Therefore, the inner grooved tube can be manufactured at a high speed. Moreover, since a mandrel is not used, a long inner grooved tube can be manufactured.
[0021]
In order to achieve the above object, the present invention has a third feature in that a plurality of grooves parallel to the tube axis are formed in the circumferential direction of the outer peripheral surface, and are disposed inside the processed tube. An inner surface comprising: a grooved floating plug; and a die which is disposed outside the processed pipe so as to face the grooved floating plug and is rotationally driven when the processed pipe is drawn. An apparatus for manufacturing a grooved tube is provided.
[0022]
According to this configuration, the grooved floating plug and the die are arranged opposite to each other with the work tube interposed therebetween, and the friction force on the surface of the work tube can be reduced by pulling out the work tube while rotating the die. Furthermore, since the groove shape of the groove forming part is a groove parallel to the tube axis, the inner surface friction due to grooving is reduced, the passage of the tube to be processed at the time of drawing the tube to be processed is improved, and breakage etc. An internally grooved tube can be manufactured at high speed without incurring defects. Further, since the structure does not have a mandrel, it is possible to manufacture a long inner grooved tube.
[0023]
In order to achieve the above-mentioned object, the present invention provides, as a fourth feature, a floating plug disposed inside the work tube and the outside of the work tube facing the floating plug. And a first die that is rotationally driven during drawing of the tube to be processed, and a pipe connected to the floating plug by a connecting rod and parallel to the tube axis. A plug in which a plurality of grooves are formed in the circumferential direction of the outer circumferential surface, a second plug that is disposed outside the pipe to be processed so as to face the plug, and is driven to rotate when the pipe to be processed is drawn. An apparatus for manufacturing an internally grooved tube is provided.
[0024]
According to this configuration, the floating plug and the grooved plug are disposed opposite to the first and second dies with the workpiece tube interposed therebetween, and the first and second dies are rotated while the floating plug and the grooved are provided. By pulling out the work tube through the plug, the friction force on the surface of the work tube can be reduced. Further, since the groove shape of the plug is a groove parallel to the tube axis, Since the friction can be reduced, the passability of the work tube at the time of drawing the work tube is improved, and an internally grooved tube can be manufactured at high speed without causing defects such as breakage. Further, since the structure does not have a mandrel, it is possible to manufacture a long inner grooved tube.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows an apparatus for manufacturing an internally grooved tube according to a first embodiment of the present invention. This configuration belongs to the drawing method, and an internally grooved tube in which a groove parallel to the tube axis is formed on the inner surface of the smooth tube can be manufactured. As described above, the internally grooved tube having a groove twist angle of 0, that is, a groove parallel to the tube axis, is suitable for applications such as an original tube of a leak detection tube, an ultrafine heat transfer tube, and the like.
[0026]
The internally grooved tube manufacturing apparatus 1 includes a die 2 that rotates during processing, and a grooved floating plug 3 that is disposed so as to face the die 2 while being inserted into a smooth tube 10 as a tube to be processed. Yes. The grooved floating plug 3 has a groove forming portion 4 at a rear end (exit side end of the smooth tube 10), and the groove forming portion 4 has parallel grooves 4a parallel to the tube axis at regular intervals in the circumferential direction. It has a constant depth and a constant width. The die 2 is attached with a holder that rotatably holds the die 2 and a drive unit that rotates the die 2, but the illustration is omitted here. The drive unit includes, for example, a motor, a reduction gear mechanism, and a control unit.
[0027]
In FIG. 1, the smooth tube 10 is inserted into the die 2 from the left side of the drawing, and the grooved floating plug 3 is inserted into the smooth tube 10 with the groove forming portion 4 as the rear end. By pulling the smooth tube 10 from the right side of the drawing and pressing the smooth tube 10 against the grooved floating plug 3 by the rotating die 2, the parallel grooves 4a of the groove forming portion 4 formed in the grooved floating plug 3 are formed. Transferred to the inner surface of the smooth tube 10. Thereby, the inner surface grooved tube 11 in which the inner surface groove 11a is formed can be obtained.
[0028]
Generally, since the tip of the floating plug has an inclined surface, a frictional resistance is generated between the inclined surface and the inner surface of the work tube. Further, in order to process a groove having a twist angle such as a spiral groove with the configuration of FIG. 1, it is necessary to rotate the grooved floating plug 3. It is difficult to process the internally grooved tube 11. Therefore, in the grooved floating plug 3 of the present embodiment, as shown in FIG. 1, the parallel groove 4a of the groove forming portion 4 is formed in a groove shape parallel to the tube axis so that the above-described problem does not occur.
[0029]
Thus, according to 1st Embodiment, the friction of the surface of the smooth tube 10 accompanying a reduction process is reduced by rotating the die | dye 2. As shown in FIG. Further, by using the grooved floating plug 3 provided with the groove forming portion 4 in which the parallel grooves 4a are formed, the inner surface friction in the process from the drawing of the smooth tube 10 to the groove cutting is reduced, and at the time of drawing the die 2 The passability of the smooth tube 10 is improved. As a result, the production speed can be increased, that is, the mass productivity can be improved without complicating the configuration and without causing trouble such as breakage of the inner grooved tube 11.
[0030]
And since it is made into the floating plug with a groove | channel, since the number of parts can be minimized, a running cost can be reduced and a maintenance check can be made easy. In particular, in recent years, it has been desired that the type of the internally grooved tube manufactured according to demand can be quickly changed. However, according to the first embodiment, the manufacturing change can be flexibly and quickly handled. It becomes possible.
[0031]
In particular, in the case of an original pipe for a leak detection pipe or a heat transfer pipe for a hot water heater that uses carbon dioxide as a refrigerant, the pipe internal pressure becomes high, so a thin and thick heat transfer pipe is required to ensure pressure resistance. However, according to the present invention, these internally grooved tubes can be provided economically.
[0032]
[Second Embodiment]
FIG. 2 shows an apparatus for manufacturing an internally grooved tube according to the second embodiment of the present invention. In the configuration of the first embodiment, since the grooved floating plug 3 is in a floating state, a long material can be processed. Also in the configuration of FIG. 1, as in FIG. 3, if the grooved floating plug 3 is gripped by a mandrel, it is possible to process an internally grooved tube having an internal groove with a large twist angle. However, since the mandrel is a constituent element, the grooving process is limited to short materials. In addition, when the mandrel is used, when the groove shape is changed due to a change in the customer or the like, it takes time to change the jig and it is difficult to quickly respond to the demand.
[0033]
Therefore, in the second embodiment, the floating plug 23 and the grooved plug 24 are connected by the connecting rod 25. Thereby, processing of the long inner surface grooved tube 11 having a large twist angle becomes possible.
[0034]
An internally grooved pipe manufacturing apparatus 20 according to the second embodiment includes a first die 21 that rotates at the time of processing, and a second die that is disposed downstream of the die 21 and has an inner diameter smaller than that of the die 21. A die 22, a floating plug 23 that is inserted into the smooth tube 10 so as to be opposed to the die 21, and a screw plug 23 that is inserted into the smooth tube 10 and coaxially arranged on the floating plug 23 and parallel to the tube axis. A parallel groove 24a is formed with a plug 24 formed at regular intervals in the circumferential direction, and a connecting rod 25 for connecting the plug 24 and the floating plug 23.
[0035]
Also in the present embodiment, the dies 21 and 22 are attached with a holder that rotatably holds the dies 2 and a drive unit that individually rotates the dies 21 and 22, but are not shown here. The drive unit includes, for example, a motor, a reduction gear mechanism, and a control unit.
[0036]
In the configuration of FIG. 2, the smooth tube 10 is inserted from the left side of the drawing so as to pass through the dies 21 and 22. Further, the plug 24 connected by the connecting rod 25 and the floating plug 23 are inserted into the smooth tube 10 with the plug 24 at the tip side. In this state, while the smooth tube 10 is pulled out from the right side of the drawing, the smooth tube 10 is pressed against the floating plug 23 by the rotating die 21, so that the parallel grooves 24 a formed on the outer peripheral surface of the plug 24 become smooth tube 10. Is transferred as an inner surface groove 11a. Thereby, the internally grooved tube 11 is obtained.
[0037]
The inner grooved tube manufacturing apparatus 20 of FIG. 2 requires a processing force in each of the first reduction processing using the plug 24 and the second reduction processing using the floating plug 23, and thus is not suitable for forming a deep groove. However, since the inner surface area of the tube can be increased, it is suitable for manufacturing heat transfer tubes and the like at low cost. Note that either the second die 22 or the first die 21 may be rotated, but in order to reduce the frictional force, both the first and second dies 21 and 22 are rotated. Is desirable.
[0038]
In the above embodiment, the parallel grooves 4a and the parallel grooves 24a are formed at a constant interval, the same width, and the same depth, but are not limited to this, and are not limited to the same interval, different widths, Different depths may be used. Further, as long as the influence of friction does not appear, it may be a groove provided with a twist angle instead of the parallel grooves 4a and 24a.
[0039]
【The invention's effect】
As is clear from the above, according to the method and apparatus for manufacturing an internally grooved tube of the present invention, a rotating die and a floating plug having a groove forming portion in which a groove parallel to the tube axis is formed are arranged to face each other. Since the work tube is inserted between the die and the floating plug, and the work tube is pulled out while rotating the die, the die and the work are processed by the rotation of the die and the groove parallel to the tube axis. The frictional resistance between the tubes is reduced, and the internally grooved tube can be processed at high speed without causing breakage or the like. Further, since a mandrel is not required, it is possible to manufacture a long inner grooved tube. In particular, it is possible to economically manufacture an internally grooved tube that requires pressure resistance, such as an original tube of a leak detection tube or a heat transfer tube for a hot water heater using carbon dioxide as a refrigerant.
[0040]
Furthermore, according to another method and apparatus for manufacturing an internally grooved tube of the present invention, the rotating first and second dies are arranged at a predetermined interval, and are opposed to the first die through the processed tube. A floating plug is arranged. Further, the plug is connected to the floating plug by a connecting rod, and the plug is arranged opposite to the second die through the work tube, and the two-stage reduction is performed while rotating the first and second dies. Since the pipe to be machined is pulled out, the friction resistance between the die and the pipe to be machined is reduced by the rotation of the die and the groove parallel to the pipe axis, and the internally grooved pipe can be formed without causing breakage or the like. It can be processed at high speed. Further, since a mandrel is not required, it is possible to manufacture a long inner grooved tube. In particular, it is possible to economically manufacture an internally grooved tube that requires pressure resistance, such as an original tube of a leak detection tube or a heat transfer tube for a hot water heater using carbon dioxide as a refrigerant.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing an apparatus for manufacturing an internally grooved tube according to a first embodiment of the present invention.
FIG. 2 is a front sectional view showing an apparatus for manufacturing an internally grooved tube according to a second embodiment of the present invention.
FIG. 3 is a schematic view showing a conventional internally grooved pipe manufacturing apparatus.
4 is a front cross-sectional view showing a detailed configuration of a processing portion and a rotation support portion of FIG. 3;
FIG. 5 is a front sectional view showing another configuration of a conventional apparatus for producing an internally grooved tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,20 Internal grooved pipe manufacturing apparatus 2 Die 3 Grooved floating plug 4 Groove forming part 4a Parallel groove 10 Smooth tube 11, 20 Internal grooved tube 11a Internal groove 21 First die 22 Second die 23 Floating plug 24 Plug 24a Parallel groove 25 Connecting rod 100 Internal grooved tube manufacturing device 101 Base portion 102 Processing portion 103 Position adjustment device 104 Mandrel 104a Stopper 105a Thrust bearing 105b Mandrel base 106 Carriage 107a, 107b Sprocket 108 Chain 109 Claw 110 Plug 110a, 301a Groove 111 Dice 200, 304 Smooth tube 201, 308 Internal grooved tube 201a, 308a Internal groove 301 Plug 302 Connecting rod 303 Floating plug 305 Processed ball 306, 307 Die

Claims (4)

A floating plug having a groove forming portion in which a plurality of grooves parallel to the tube axis are provided in the circumferential direction of the outer peripheral surface is disposed inside the pipe to be processed,
A die is arranged outside the processed pipe so as to face the floating plug,
A method of manufacturing an internally grooved tube, wherein the tube to be processed is pulled out while rotating the die, and the tube to be processed is reduced and internally grooved. A floating plug is placed inside the machined pipe,
A first die is disposed outside the processed pipe so as to face the floating plug,
A plurality of grooves parallel to the tube axis are formed in the circumferential direction of the outer peripheral surface, and the plug is disposed inside the processed tube in a state of being connected to the floating plug by a connecting rod,
A second die is disposed outside the work tube so as to face the plug,
A method of manufacturing an internally grooved tube, wherein the tube to be processed is drawn while rotating the first and second dies, and the tube to be processed is reduced and internally grooved. A plurality of grooves parallel to the tube axis are formed in the circumferential direction of the outer peripheral surface, and a grooved floating plug disposed inside the processed tube;
An apparatus for producing an internally grooved pipe, comprising: a die which is disposed outside the pipe to be processed so as to face the floating plug with the groove, and which is rotationally driven when the pipe to be processed is drawn. . A floating plug disposed inside the work tube;
A first die which is disposed outside the processing tube so as to face the floating plug, and is rotationally driven when the processing tube is drawn;
A plug in which a plurality of grooves parallel to the tube axis are formed in the circumferential direction of the outer circumferential surface while being connected to the floating plug in a state of being connected to the floating plug by a connecting rod;
An apparatus for producing an internally grooved pipe, comprising: a second die which is disposed outside the pipe to be processed so as to face the plug and which is rotationally driven when the pipe to be processed is drawn. .

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